This application claims priority under 35 U.S.C. xc2xa7xc2xa7119 and/or 365 to Appln. No. 199 56 042.0 filed in Germany on Nov. 22, 1999; the entire content of which is hereby incorporated by reference.
The invention relates to the field of rotating electrical machines. It is based on a rotor for a high-speed electrical machine.
Electrical high-speed rotating machines, in particular asynchronous machines, normally have a rotor which comprises a laminated core. DE 693 11 530 T2 discloses such a rotor. A short-circuiting ring is attached to each of the two end faces of the laminated core. The short-circuiting rings connect the short-circuiting bars, in which case the short-circuiting bars pass through the laminated core in the circumferential direction. The short-circuiting rings with the short-circuiting bars form a cage winding. Furthermore, according to DE 693 11 530 T2, in each case a shaft stub is centrally attached to the end faces of the rotor, of which shaft stubs at least one serves to transmit the rotary movement of the rotor, for example, to a unit to be driven. Each shaft stub rests on the respective short-circuiting ring. Furthermore, tie rods jointly pass through the laminated core, the short-circuiting rings and the shaft stubs in the circumferential direction. The tie rods serve to hold the laminated core together, these tie rods being supported on the shaft stubs and pressing the short-circuiting rings against the laminated core.
The ends of the shaft stubs are guided in a conventional manner by bearings, and a coupling device is generally provided at least at one end.
A problem with the rotor according to DE 693 11 530 T2 is that a high axial force is required in the tie rods in order to be able to achieve suitable rigidity of the entire rotor and in particular of the laminated core during high-speed operation. There is no defined bearing surface of the individual laminations, since the laminations of the rotor are subject to production tolerances and have waviness, with the result that an asymmetrical rotor assembly may be produced during the stacking of the laminations. This may lead to nonconcentric running of the rotor during operation and to complicated additional balancing measures for achieving uniform concentric running of the rotor.
Furthermore, DE 573512 discloses a turbogenerator rotor of high rigidity, which is composed of welded disks lined up next to one another, the disks being provided with prominences and recessed portions at the end faces.
However, the design of the rotor according to DE 573512 is complicated due to the requisite welding of the disks and is thus expensive to produce. In addition, the disks, in particular the prominences and recessed portions, have to be produced very exactly, so that they engage one inside the other in an accurate manner. This increases the production costs considerably.
The object of the invention is therefore to specify a rotor for a high-speed electrical machine, which rotor is especially rigid at high speeds and in addition is constructed in a very simple and thus cost-effective and easy-to-maintain manner.
The rotor according to the invention has a stack of several thick solid disks which are lined up next to one another and have a defined pressing surface at their end faces. Furthermore, tie rods pass through the stack in the axial direction in the region of and/or close to the pressing surface, the tie rods pressing the solid disks against one another. As a result, an extremely rigid rotor assembly, which is necessary for high speeds, is obtained in an exceptionally advantageous manner. Furthermore, the rotor has excellent flexural rigidity during thermal loads. In addition, the solid disks can be produced in a very simple and cost-effective manner, for example by turning.
Furthermore, the pressing surfaces are advantageously located essentially in the marginal region and/or close to the marginal region of the end faces of the solid disks and are designed according to the invention essentially as annular surfaces, so that high flexural rigidity with at the same time low axial forces in the tie rods and thus especially smooth concentric running of the rotor are achieved in this region of the solid disks, which, is especially subjected to stress by centrifugal forces at high speeds. In addition, due to these excellent concentric running properties, the shaft bearings of the rotor and of units to be driven which are coupled to shaft ends of the rotor will be subjected to considerably less wear.